Creating Pie Charts
With Pyplot, you can use the pie() function to draw pie charts:
Example
import matplotlib.pyplot as plt
import numpy as np
y = np.array([35,
25, 25, 15])
plt.pie(y)
plt.show()As you can see the pie chart draws one piece (called a wedge) for each value in the array (in this case [35, 25, 25, 15]).
By default the plotting of the first wedge starts from the x-axis and moves counterclockwise :
Note
The size of each wedge is determined by comparing the value with all the other values, by using this formula:
The value divided by the sum of all values: x/sum(x)
Labels
Add labels to the pie chart with the labels parameter.
The labels parameter must be an array with one label for each wedge:
Example
import matplotlib.pyplot as plt
import numpy as np
y = np.array([35,
25, 25, 15])
mylabels = ["Apples", "Bananas", "Cherries", "Dates"]
plt.pie(y,
labels = mylabels)
plt.show()Start Angle
As mentioned the default start angle is at the x-axis, but you can change the start angle by specifying a startangle parameter.
The startangle parameter is defined with an angle in degrees, default angle is 0:
Example
import matplotlib.pyplot as plt
import numpy as np
y = np.array([35,
25, 25, 15])
mylabels = ["Apples", "Bananas", "Cherries", "Dates"]
plt.pie(y,
labels = mylabels, startangle = 90)
plt.show()Explode
Maybe you want one of the wedges to stand out? The explode parameter allows you to do that.
The explode parameter, if specified, and not None , must be an array with one value for each wedge.
Each value represents how far from the center each wedge is displayed:
Example
import matplotlib.pyplot as plt
import numpy as np
y = np.array([35,
25, 25, 15])
mylabels = ["Apples", "Bananas", "Cherries", "Dates"]
myexplode = [0.2, 0, 0, 0]
plt.pie(y,
labels = mylabels, explode = myexplode)
plt.show()Shadow
Add a shadow to the pie chart by setting the shadows parameter to True :
Example
import matplotlib.pyplot as plt
import numpy as np
y = np.array([35,
25, 25, 15])
mylabels = ["Apples", "Bananas", "Cherries", "Dates"]
myexplode = [0.2, 0, 0, 0]
plt.pie(y,
labels = mylabels, explode = myexplode, shadow = True)
plt.show()Colors
You can set the color of each wedge with the colors parameter.
The colors parameter, if specified, must be an array with one value for each wedge:
Example
import matplotlib.pyplot as plt
import numpy as np
y = np.array([35,
25, 25, 15])
mylabels = ["Apples", "Bananas", "Cherries", "Dates"]
mycolors = ["black", "hotpink", "b", "#4CAF50"]
plt.pie(y, labels =
mylabels, colors = mycolors)
plt.show()You can use Hexadecimal color values , any of the 140 supported color names , or one of these shortcuts:
'r' - Red 'g' - Green 'b' - Blue 'c' - Cyan 'm' - Magenta 'y' - Yellow 'k' - Black 'w' - White
Legend
To add a list of explanation for each wedge, use the legend() function:
Example
import matplotlib.pyplot as plt
import numpy as np
y = np.array([35,
25, 25, 15])
mylabels = ["Apples", "Bananas", "Cherries", "Dates"]
plt.pie(y, labels = mylabels)
plt.legend()
plt.show()Legend With Header
To add a header to the legend, add the title parameter to the legend function.
Example
import matplotlib.pyplot as plt
import numpy as np
y = np.array([35,
25, 25, 15])
mylabels = ["Apples", "Bananas", "Cherries", "Dates"]
plt.pie(y, labels = mylabels)
plt.legend(title = "Four Fruits:")
plt.show()